1. Field of the Invention
The present invention relates to a terminal connection structure of a resolver stator coil. In particular, the present invention relates to a novel and improved connection structure in which a part of an end portion of a stator coil wound around a terminal is left as a free end without integrating it with the terminal by soldering or the like, whereby any expansion/contraction caused by a temperature change or a vibration generated in the stator coil is absorbed by this free end, and rupture or breakage of the stator coil is prevented, thereby improving the resolver in terms of reliability.
2. Description of the Related Art
FIGS. 5 and 7 show a typical conventional connection structure of the stator coil of the resolver of this type.
In FIG. 5, reference numeral 1 indicates a stator coil provided on a resolver stator 2. An end portion 3 of this stator coil 1 is wound around a terminal 4 protruding from an insulation mold 10 provided on the stator 2, to which varnish coating or the like is applied.
The end portion 3 wound around the terminal 4 constitutes a winding connecting portion 5, which is entirely covered with solder 6, as shown in FIG. 7. By means of this solder 6, the end portion 3 is connected with the terminal 4 so as to form an integral portion.
In addition to the soldering, fusing is also performed to form the integral connection between the end portion 3 and the terminal 4. In this case, the end portion 3 of the stator coil 1 is fused by heating to form the integral connection with the terminal 4.
The conventional terminal connection structure of the resolver stator coil is constructed as described above, thereby involving the following problem.
Soldering is performed entirely to the end portion wound around the terminal as shown in FIG. 7. Therefore, when the resolver is manufactured in the state shown in FIG. 7, and then is mounted to an automobile, machine tool, etc. for operation, stress caused by thermal expansion, vibration, etc. is applied to various portions of the stator. As a result, as shown in FIG. 8, this stress causes the stator coil to be broken and cut down from the terminal, i.e., a base 1a of the soldered portion thereof, and the resolver ceases to operate as such.
The base portion 1a is fixed by soldering or the like, any vibration or expansion/contraction of the stator coil is hard to absorb, resulting in breakage of the end portion 3.